This invention relates to alkenyl phosphonic and -phosphinic acid esters of certain polyhydric alkanols, a process for their preparation, and radiation-polymerizable mixtures containing these esters as polymerizable compounds.
Esters and other derivatives of alkenyl phosphonic and -phosphinic acids with usually monohydric alcohols are known and are employed on a large industrial scale for the preparation of polymers, for example of polyvinylphosphonic acid and its derivatives. Direct utilization of the unsaturated compounds mentioned--apart from the preparation of polymers--has hitherto only been carried out to a small extent, virtually only the acidic properties of the monomers being used without the polymerizability of the alkenyl group being utilized. This is presumably attributable to the relatively low tendency towards polymerization of the known alkenyl phosphonic acids or their derivatives, which is mentioned in DE-C No. 1,106,963.
Photopolymerizable mixtures for the production of printing plates and for the preparation of photoresists and other photosensitive materials contain compounds which can be polymerized by the action of actinic light, in the presence of a photoinitiator to form cross-linked, insoluble products. Compounds of this type which have been employed hitherto are virtually exclusively esters of unsaturated carboxylic acids, in particular of acrylic acid and methacrylic acid, with polyhydric aliphatic or cycloaliphatic alcohols, which may optionally contain urethane or ether groups. In earlier publications, for example in U.S. Pat. No. 2,892,716, divinyl esters of aromatic or aliphatic disulfonic acids are mentioned as polymerizable compounds, but these have not been introduced into practice.
The (meth)acrylates of polyhydric alcohols which have been preferred hitherto have certain disadvantages, at least for some applications. They are unstable at elevated temperatures, for example above 150.degree. C.; in addition, many low-molecular-weight representatives have high volatility, which becomes noticeable on relatively long storage in the coating and on processing at elevated temperatures. In addition, most of the preferred representatives are water-insoluble and thus rather difficult to combine with water-soluble or hydrophilic binders. Additionally, most (meth)acrylates cause harmful skin irritations.